Expression Products of Chimeric BMP2 and BMP7 Induce Osteoblast Differentiation / 天津医药

ABSTRACT

Objective: To study the osteoinductive activity of chimeric molecule of bone morphogenetic protein(BMP)2 and BMP7 expressed in mammalian cells. Methods: Sequences encoding mature peptides of BMP2 and BMP7 were separately amplified by PCR and then linked by overlap-extension PCR with a DNA sequence encoding a flexible peptide (Gly_4Ser)_3 between them. The chimeric DNA sequence was cloned into secretory expression plasmid pcDNA3/sec and then the recombinant plasmid pcDNA3 -BMP2/7 was transfected into CHO-K1 cells. In the presence of G418,cells that stably expressed BMP2/7 were screened out. Thereafter, the conditioned culture medium of the transfected cells was collected and used to treat C3H10T1/2 cells. RT-PCR was employed to study the activity of the recombinant product in inducing osteoblast differentiation. Results: The expression products of chimeric BMP2/7 significantly enhanced the mRNA expression levels of osteoblast phenotype genes, such as alkaline phosphatase, osteocalcin and osteoblast specific transcription factor runt-related transcription factor 2 in C3H10T1/2 cells(P < 0.01). Conclusion: The chimeric expression products of BMP2/7 are capable of forming heterodimers and thus effectively induce non-bone derived cells to differentiate into osteoblasts.